Journal of clinical epidemiology
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To determine how often stepped-wedge cluster randomized controlled trials reach their planned sample size, and what reasons are reported for choosing a stepped-wedge trial design. ⋯ About half of recently published stepped-wedge trials reached their planned sample size indicating that recruitment is also a major problem in these trials. Still, the stepped-wedge trial design can yield practical, ethical, and methodological advantages.
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Network meta-analysis (NMA) is increasingly being used to synthesize direct and indirect evidence and help decision makers simultaneously compare multiple treatments. We empirically evaluate the incremental gain in precision achieved by incorporating indirect evidence in NMAs. ⋯ Although NMAs have the potential to provide more precise results than those only based on direct evidence, the incremental gain may reliably occur only when at least two head-to-head studies are available and treatments are well connected. Researchers should routinely report and compare the results from both network and pairwise meta-analyses.
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Randomized Controlled Trial
A data-sharing agreement helps to increase researchers' willingness to share primary data: results from a randomized controlled trial.
Sharing individual participant data (IPD) among researchers, on request, is an ethical and responsible practice. Despite numerous calls for this practice to be standard, however, research indicates that primary study authors are often unwilling to share IPD, even for use in a meta-analysis. This study sought to examine researchers' reservations about data sharing and to evaluate the impact of sending a data-sharing agreement on researchers' attitudes toward sharing IPD. ⋯ These findings shed light on data-sharing practices, attitudes, and concerns and can be used to inform future meta-analysis projects seeking to collect IPD, as well as the field at large.
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When direct and indirect estimates of treatment effects are coherent, network meta-analysis (NMA) estimates should have increased precision (narrower confidence or credible intervals compared with relying on direct estimates alone), a benefit of NMA. We have, however, observed cases of sparse networks in which combining direct and indirect estimates results in marked widening of the confidence intervals. In many cases, the assumption of common between-study heterogeneity across the network seems to be responsible for this counterintuitive result. ⋯ The result, however, may be spuriously wide confidence intervals for some of the comparisons in the network (and, in the Grading of Recommendations Assessment, Development, and Evaluation approach, inappropriately low ratings of the certainty of the evidence through rating down for serious imprecision). Systematic reviewers should be aware of the problem and plan sensitivity analyses that produce intuitively sensible confidence intervals. These sensitivity analyses may include using informative priors for the between-study heterogeneity parameter in the Bayesian framework and the use of fixed effects models.
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To examine, through a cross-sectional survey, how well safety information was reported among drug systematic reviews predating PRISMA harms checklist and explore factors associated with better reporting. ⋯ The reporting of safety information was poor both for Cochrane and non-Cochrane drug systematic reviews predating PRISMA harms checklist. The findings suggested a strong need to use the PRISMA harms checklist for reporting safety among drug systematic reviews.